DSCS (Defense Satellite Communications System)

DSCS 3 satellite.

DSCS (Defense Satellite Communications System) is the United States Department of Defense global network of strategic communications
satellites, referred to as 'Discus'. DSCS provides uninterrupted secure
voice and high data rate communications between major military terminals
and national command authorities. It was developed in three phases. The
first was originally known as IDCSP (Interim
DSCS) but renamed DSCS 1 upon becoming operational. The second phase involved
much larger spacecraft placed in true geosynchronous
orbits between 1971 and 1975. Seven of these were still working in 1982
when the first DSCS 3 satellites were launched. A constellation of six DSCS
3 satellites (four operational and two spares) in geosynchronous orbit is
now up and running.